Rock bit



Aug. 20, 1957 w. D. MGEACHERN ROCK BIT Filed MaIOh 25, 1953 IVNVENTR.

United States Patent ROCK BIT Wallace D. McEacher-n, Odessa, Tex.

Application March 23, 1953, Serial No. 344,013

3 Claims. (Cl. Z55-313) This invention relates to a method and means of lubrieating rotary cone rock bits and more particularly, but not by way of limitation, to a method and means of cleaning and cooling a rock bit by concentration of a lubricating fluid within the bit.

As is well known in the art, the lubrication of the rotary cone rock bits utilized in rotary drilling of oil wells is usually provided through mud and water from a pump at the surface of the well circulating through the drilling string and discharged from the rock bit at the bottom of the well bore. The fluid circulation in rotary drilling has two definite purposes, one is to lubricate and cool the bearings of the cutters from the heat generated during rotation thereof, and the other is to remove the cuttings which are being ground out of the well bore.

It has been found that in certain geological formations the rotation of the rock bit substantially pulverizes the strata being drilled, thereby causing a considerable amount of dust which will accumulate in the bearings, or the cone teeth and must be removed to prevent locking of the cutter cones. While liquid has been used in the past for removing cuttings from well bores, the use of compressed air to blow out pulverized cuttings to prevent accumulation of dust usually behind the cones and the bearings has been satisfactory. The compressed air utilized for cleaning the cones and removing the pulverized cuttings, also acts as a lubricator and cooling medium for the bearings from the heat generated by the cone rotation. The temperature generated by the rock bits may be as high as live to six hundred degrees Fahrenheit which obviously causes the bearings to wear much faster, and reduce the eiciency of the bit in general.

It is known in the art that air has been used for a cooling and cleaning medium in rotary drilling. Usually the size of the opening of the longitudinal passageway in the center of the bit shank has been reduced and then providing small openings leading into each cone. Also the opening has been enlarged to maximum diameter. However, both methods have proven unsatisfactory to efficiently clean the cones and cool the bearings at the same time.

The present invention is generally concerned with the utilization of a baille plate placed beneath the cones of a multiple rotary cone bit, such as a two or three cone bit being utilized today in drilling operations. It is to be understood that the baie may be used with a bit having any number of cones by simple modification. The baiile plate is constructed to direct the air from the drill string, and enter the longitudinal passageway of the bit shank where it is directed in a manner to concentrate the projection of the air for a uniform over-all distribution throughout all the cones, thereby providing an eicient cooling of the bit, as well as cleaning and removing the pulverized cuttings from the bit and onto the top of the well.

It is an important object of this invention to clean a roller cone rock bit in such a manner that all cuttings ICC accumulated within the bit are eiciently removed therefrom along with a simultaneous cooling of the bit.

And still a further object of this invention is to direct compressed air through a roller cone rock bit in such a manner that any accumulation of dust within the teeth or bearings of the bit from pulverized cuttings is removed in an eicient and expeditious manner simultaneous with a cooling of the bit proper.

Another object of this invention is to utilize a pressure uid as a medium for cleaning accumulated pulverized dust cuttings from a rotary rock bit in such a manner that the heated bearings are simultaneously cooled at a point conterminous with the jointure of the bit cone and supporting spindle so that the fluid is then directed from the rear of the cones forward through the bit.

Other objects and advantages of the invention will be evident from the following detailed description, read in conjunction with the accompanying drawings, which ily operate by threaded engagement with a drill collar or drill string (not shown). The tapered shank is integral with a head 6 having a plurality of extended legs 8, 10 and 12 in the usual manner. The rock bit is constructed v with the usual clefts or notches 14 provided between each of thelegs. The tapered shank is provided with a longitudinal passageway 16 having a reduced diameter at 18 extending into a discharge outlet 20. The legs are each provided with the usual inwardly inclined shafts 22 for receiving the roller cutter cones 24 secured thereon by suitable bearing members in a manner not shown. As is clearly shown in Fig. l, two of the cones 24 are partially cut away, along with a portion of the legs 8 and 10 for purposes of illustration. The roller cutter cones 24 have the usual chisel teeth 26 and are preferably of the interfltting type, although not necessarily limited thereto.

The continuous rotation of the cutter teeth pulverize the cuttings from the geological strata to the extent that i compressed air can be directed through the ususal longitudinal passage 20 for blowing the cuttings to the top p of the well. However, it is necessary to cool the bearings and the cutter teeth, thereby reducing the temperature of the heat generated by the rock bit, sometimes running as high as 500 or 600 degrees Fahrenheit. In order to utilize compressed air for removal of the cuttings with a smiultaneous cooling of the cutter teeth and bearings, it is necessary to concentrate the direction of the air, into and through, the rock bit. In order to provide this concentration, a bale plate 2S is provided and is preferably disposed within the rock bit 2 during the manufacturing assembly of the bit prior to the mounting the cutter cones 24 on the Shanks 22.

As is clearly shown, the plate 28 is of a substantially triangular configuration having a central aperture 30 of a smaller diameter than the reduced bore 18 for purposes as will be hereinafter set forth. The apex 32 of each preferably rounded corner of the triangle, Fig. 2 (although they may be pointed, Fig. 1), is adapted to beA disposed in the notch 14 between the leg members of the rock bit 2 so that positioning of the plate 28 within the,

bit is facilitated. The plate 28 is disposed in such a manner that the apexes 32 thereof engage the bottom of the notches 14 and abut inner surfaces of the leg members 8, 10 and 12. Furthermore, the plate 28 is slightly spaced from the bottom or inside portion 34, of the head 6 because of the slight curvature of Vthe inside portion 34,7^ as shown in Fig. l, thereby providing a chamber 35 between the head 6 and the plate 278 for dispersement of the air moving through the bore 2b and into Contact with the plate 2,8, as will be hereinafter set forth. The plate. 28 is preferably welded to the inner surfaces of the leg members 8, 10 and 12 at points 33 adjacent the notches 14 in any well known manner (not shown) whereby air cannot flow around the plate 28 through the notches 14. It is to be understood that the securing of the plateV toV the bit is not limited to welding, but may be secured by ahy Suitable means The triangulrplate 28. is. provided with a plurality Of recesses Or; notches 36. along, @achtunginal edge thereof-S that With the plate. 2,8. in Position: the notches are substantially centrally disposed against the inner periphery 0f. each ofthe legsV 8, 10 r 12 as iS clearly shown in Fig. 2, A portion of the air howing through the reduced bore 1S will be deflected by the plate member 28 since the central bore 30 ofthe plate is of a VSmaller. diameter thanlhf bor@ 13.V Thus. a portion, ofthe air will be deflected into the chamber 35, wherein the air will tend to seek the line ofleast resistance and ow through the notches 36, as will be hereinafter set forth.

After the roller cutter cones 24 have been` mounted on the shanks 22, it will be apparent that a notch 36 is disposed beneath a cutter Acone and substantially adjacent the heel teeth of each cutter cone 24, The disposition of the edge-wise slots 36 substantially conterminous with the back portion of the cutter cones 24 places them in proximity of the bearing recess for a purpose as will be hereinafter set forth. The aperture 30 substantially conforms to the diameter of the small bore 20 in the head 6 of the rock bit 2.

Operation In operation,y compressed air from any suitable compressor (not shown) at the surface of the well is directed through the drill string( andinto the .longitudinal passage 16 and through the passageway 18 where a portion ofthe air will be deflected by the plate 28 because the aperture 30 is of a smallerV diameter than the bore 18. The deflectedair is directedbetween the bottom of the bathe plate 28 and the face 34 ofthe head 6 and-hence discharged through theedgre-wise slot portions36, since the air will tend to seek the line of leastresistance, and escape from the chamber 35 through theopenings 36. It will be4 Vapparent thaty the edge-wisev slots` may vary in inclination and while it isV preferable to incline the slots preferably between forty-tive or sixty degrees for directing the air upwardly through the individual cutter cones 24, the invention is not limited to any specific angled inclination of the slots 36.

The diverting or channeling of the airV to the baci; teeth or heel section of the cutter cone where the spindles Y22 and the cuttersrare joined facilitatesA the cooling of theV cones and bearings of the rock bit 2. Furthermore, the concentrated direction of air provides for cleaning of the cones by preventing accumulation of pulverized cuttings between Vthe interstices of the teeth 26 on the interitting cone members. The stream of air is channeled by the bathe plate to the point of attachment to the cutter cones 24 andby removing any excess accumulation of dustprevents locking of the cones,V thereby providing free rolling thereof at all times. Y Y

In addition to the divertingof the air by the bathe plate 28 through the edge-wise slots 36 a portion of the airV discharges throughV theaperture- 30 in the center of the bathe plate 28 and co-mingles Withthe air moving from beneath the cutter cones outwardly therethrough, therebyV materially assisting in removing all cuttingsv and accumuf lateddust fromv the roch bit to. the outside. of the drill in which the bit is drilling.

4 pipe in order to be displaced to the surface of the well, It will be apparent that use of the adapter bathe plate 28 is not limited to air, and water or other fluids may be utilized if desired for effecting a cooling and removal of cuttings from the rock bit. As heretofore mentioned, the inclination and size of the edge-wise slots 36 is variable, and depends to a great extent upon the formation if air is used entirely, the slots can usually be smaller and off less degree of inclination, whereas if the cleaning and cooling huid is water, the slots may be larger and ofV greater incline. It will thus be seen that the bathe plate provides flexibility of control in variable sizes for the same size rock bit, and the adapter plate 28 can be made in a number of sizes corresponding Yto the size rock bit with which it is desired to be used.

It will be understood that the variations of the marginal slot control of the adapter plate 28 is also dependent upon geological structure as stated, such as, for example, in a sticky, gummy surface it would be preferable to use larger slots, whereas in al hard chert formation the slots` being assembled,` it will be apparent thatfin bits alreadyV assembled a bathe plate utilizing the marginaly edge slots 36 may also be secured beneath the individual cones. lt is only necessary to cut the triangular bathe plate 28 into a plurality of sections 40j preferably three (Fig. 3), but not limited thereto, so that each section 4 9 will slip through a notch or cleft 14 between the legs and form a bathe abovethe longitudinal passageway 16. Of course,

each individual'l section plate 40 has a marginal edge slot 36 adapted to be disposed beneath the heel teeth of each cone 24 for the purpose as previously set forth. One adaptation of separate sections isrshown in Fig. 3. However, it isl not limited to. that particular disclosure and may beV modified tovariable extents as long as the edge slotsY 36 are disposed at the rear of each cutter cone 24 and beneath the cone. Also the aperture 3Q should be in substantial alignment` with the longitudinal bore 2Q. These individual bathe plates may be welded, or secured in any suitable manner to the faceriofthe head 6 and function to. divert the ,:ornpressed air through the marginal slots into contact with the back side andheel teeth. 0f the, UdVtlllCllffCr CQnesZL. f

From the foreoing, it will be apparent that the present inventionrcontemplates modification of a rotary rock bit having al plurality of cutter'cones thereon by dispositionof abafhe plate between the bit headV and the cutter cones i for diverting or' channelingV compressed air or similar uid through the center of the bit and also at the base of each' cone, thereby'concentratinU the how ofthe compressed v. Y

air at the point where locking is prevalent due to, accu-Y mulateddust or the .like in order to remove the dust with .a simultaneous.V cooling. of the bearings, Furthermore,

the compressedV air moves. from the base through. the interstices. of the teeth in conjunction with the air moving through the central portion of therbitin order to eiect a complete cooling and cleaning of the bit throughout.V

Y Changes may be made in the combination andarrangement of parts as heretofore set forth inzthe specification` and shown in therdrawings, it being understood that any` modification inthe precise embodimentof the invention may be made withinthe scope of the following claims without departing from the yspirit ofthe invention.

What is claimed is:

l.` In` a roller. rock bit comprising a head, a plurality of spacedleg. members provided on'the head, a `conical cutter mounted for rotation on each of the legs, a plurality of teeth on the cutters, a longitudinal passageway in the head providing a circulation of uid through the bit, a bafe plate mounted above the conical cutters and having the edge portions thereof disposed adjacent the heel teeth of the cutters, a plurality of elongated slots provided on the edge portions of the baie plate wherein one of the slots is disposed adjacent the heel teeth of a cutter cone, said battle plate spaced from said head and having the corners thereof adjacent the legs for cooperation therewith to provide a compartment between the plate and head, said compartment providing communication between the slots and the longitudinal passageway for directing a portion of the fluid discharging therethrough to the slots and into contact with the leg members wherein the air is diverted to and through the cutter teeth, and an aperture provided in the baffle plate in substantial alignment with the longitudinal passageway for directing the remaining portion of the fluid proximity with the apex of the cutter cones, and said baie plate member secured to said head member whereby the edge portions are sealed adjacent the leg members in order that the uid will pass only through the plate aperture and slots.

2. 1n a roller rock bit comprising a head, a plurality of spaced leg members provided on the head, conical shaped cutters mounted for rotation on each of the legs and having a plurality of intertting teeth, a longitudinal passageway in the head communicating with the cones and providing circulation of compressed air therethrough, an attenuated segmental baie plate of substantially triangular contiguration mounted above the cutter cones and having the edge portions thereof disposed adjacent the heel teeth of the cutter cones, an aperture provided in the balie plate' in alignment with the passageway, a plurality of edge-wise slots provided in the segmental baie plate wherein one slot is disposed adjacent the rear base portion of a cone, said baie plate spaced from the head in order to direct a portion of the compressed air to the slots and into contact with the base of the legs wherein the legs will divert the air to the cutters for cleaning any accumulated pulverized cuttings therefrom simultaneous with a cooling of the bearings, said plate secured to said head whereby the aperture provides for discharge of the remaining portion of the air into the proximity of the apex of the cutters.

3. ln a roller rock bit comprising a head, a plurality of spaced leg members provided on the head, a conical cutter mounted for rotation on each of the legs, a plurality of teeth on the cutters, a longitudinal passageway in the providing for circulation of uid through the bit, an attenuated baie plate of substantially triangular configuration mounted above the conical cutters and having the edge portion thereof adjacent the heel teeth of the cutters, a plurality of elongated slots provided in the baile piate along the edge portion thereof wherein one of the slots is disposed adjacent the heel teeth of the cutter zone, said baie plate spaced from said head and cooperating with the legs to provide a compartment therebetween, said compartment providing communication between the slots and the longitudinal passageway for directing a portion of the fluid discharging therethrough to the slots and into contact with the legs for diversion to and through the teeth, an aperture provided in the baiiie plate in alignment with the longitudinal bore for directing the remaining portion of the fluid into the proximity of the apex of the conical cutters, said baie plate secured to the head with the edge portions sealed whereby the iluid will pass through the aperture and slots only.

References Cited in the le of this patent U TED STATES PATENTS 1,778,966 Stokes Oct. 21, 1930 1,910,210 Harnaker May 23, 1933 2,147,927 Scott Feb. 2l, 1939 2,167,393 Muncy July 25, 1939 2,249,578 Phipps July l5, 1941 2,329,745 Crook sept. 21, 1943 2,682,389 Baker June 29, 1954 

